Flashcards
biology chapter 5
Cards in this deck (109)
- 1integumentary system- skin
- accessory organs - hair, nails, and glands
- cutaneous sensory receptores - 2dermatology- medical specialty that works with skin
- study of diseases and treatment - 3structure of the skin- skin - attached to muscle tissue via fascia
- or attached directly to bone or to ligaments
- 2 regions of the skin
- skin - cutaneous membrane - 42 regions of the skin- epidermis
- dermis - 5the epidermis- outrmost skin region
- keratinized stratified squamous epithelium
- keratinocytes
- 5 epidermal layers - 6keratinocytes- make keratin
- keratinization - hardining process
- cell rise from basal layer to surface requires 4 - 6 weeks
- cells become starved of oxygen and nutrients
- cells die (by apoptosis) and slough off as skin squames
- psoriasis - 75 epidrmal layers- stratum basale
- stratum spinosum
- startum granulosum
- stratum lucidum
- stratum corneum - 8stratum basale- one cell thick
- separated from dermis by basement membrane
- tonofilaments = keratin intermediate filaments
~ insert into plaques of desmosomes and hemidesmosomes
- mostly keratinocyte stem cells and some melanocytes adn tactile epithelial
- each dividing keratinocyte stem cell ~> one daughte remains as a stem cell in stratum basal and one daughter cell rises to next stratum - 9stratum spinosum- a spiny 8-10 cell thick layer of polyhedral cells
- spined in this layer = an artifact
~ tissue processing ~> cell shrinkage exposing tonofilaments which look like spines
- basally-located melanocytes transfer melanin pigment to keratinocytes in this stratum - 10intraepidermal macrophages- 'langerhans cells'
- antigen-prosenting cells that help cytotoxic T-lymphocytes of the skin - 11stratum granulosum- 3-5 cell thick layer of flattened cells
- outermost cells begin to die by apoptosis
- 2 types of cell granules - 122 types of cell granules- keratohyalin granules
- lamellar granules - 13keratohyalin granules- keratohyalin converts tonofilaments into hard keratin bundles
- 14lamellar granules- membrane-bound lipids release by exocytosis
- extracellular lipids ' waterproof' skin
- hard keratin produces + lipid ~> 'vinyl raincoat' - 15stratum lucidum- clear 4 - 6 cell thick layer
- translucent, flat, and dead cells
- *only present in thick skin (hairless skin)
- makes skin more tough and resilient - 16stratum corneum- uppermost and thickest epidermal layer
- 'horny layer'
- 25-30 cell layers thick (average)
- flat, hard, dead cells
- extracellular lipids between cells
- skin squames
- callus - 17skin squames- flakes of dead skin that flake on surface
- 18callus- abnormal thickening of stratum corneum causd by chronic friction
- 19non-keratinocytes found in epidermis- melanocytes
- intraepidermal macrophages
- tactile epithelial cells - 20melanocytes- make melanin
- synthesized from tyrosine in melanosomes using tyrosinase
- variations in skin color due mainly to amout and types of melanin and their distrobution
~> not due to number of melanocytes - 21sun tanning- increasesed melanin in skin
- protects skin keratinocytes from possible UV-induced chromosomal damage - 22skin freckles- patchy accumulations of meanin in skin
- fade in winter - 23age (liver) spots- similar to freckles; do not fade
- 24albinism- genetic defect~> inability to produce melanin
- cause: absence of tyrosinase, required from melanin synthesis - 25vitiligo- skin disorder, producing irregular white patches surrounded by normally pigmented skin
- cause: autoimmunity - 26melanocytic nevi (moles)- skin growths caused by accumulation of melanocytes
- 27intraepidermal macrophages (langerhans cells)- deddritic cells from bone marrow
- involved in immune mechanisms in skin
~> antigen-presenting cells help cytotoxic T-lymphocytes kill macrophages - 28tactile elithelial cells (merkel cells)- in stratum basale of hairless skin
- tactile epithelial cell synapses with tactile disc at end of a sensory neuon
- detect some touch stimuli - 29dermis- thicker than epidermis
- 2 regions
- dermal blood vessels affect skin coloration
- epidermal ridges
- skin wrinkling - 302 regions of the dermis- papillary region
- reticular region - 31papillary region of dermis- areolar connective tissue
- dermal papillae increase surface area of dermis - 32dermal papillae- nipple-shaped structure protrudes into epidermis
- found within drmal papillae: touch corpuscles, free nerve endings, capillary loops - 33free nerve endings- dendrites of sensory neurons
- transduse pain, warm/cold, tickle/itch stimuli - 34reticular region of dermis- dense irregular connective tissue containing collagen, reticular, and lastic fibers
- makes tissue strong, flexible, and elastic
- contains motor and sensory nerve fibers innervating dermal sebaceous glands, sudorriferous glansd, arrector pii muscles
- contains blood vessels to nourish dermis and epidermis
- may contain hair folecles
- overlies subcutaneous tissle (hypodermis) - 35how do dermal blood vessels affect skin coloration- blushing: due to vasodilation of dermal blood vessels
- pallor: due to vasoconstriction of these vessels
- cyanosis: bluish-grey coloration of skin due to decreased oxygenated blood in vessels - 36vasoconstriction- contraction of the smooth muscle in the walls of blood vessels
- 37epidermal ridges (fingerprints and footprints)- surface of thick skin, shows epidermal ridges separated by grooves
~ surface of ridges and grooves are associated with interpapillary pegs
- epidermal ridges ~> various pattern on skin surface - 38interpapillary pegs- interpapillary pegs penetrated by sweat gland ducts ~> epidermal ridges
- interpapillary pegs not penetrated by sweat gland ducts ~> surface grooves - 39function of epidermal ridges1. improve griping surface
2. amplify tactile vibrations
- apidermal ridges are only seen in thick skin
~ thin skin has no epidermal rigdes - 40dermatoglyphics of epidermal ridges- epidermal ridges unique to each person
- used by forensics to identify individuals
- fingerprints arise from transfer of sweat solutes onto a smooth surface
- fingerprint patterns do not change - 41skin wrinkling- excessive exposure to UV rays ~> prematurely skin aging
- uVA radiation ~> reactive oxygen species (ROS) ~> extracellulsr matrix damage
- ROS can ~> seperation of dermis from epidermis - 42accessory structures of the skin- hair
- nails
- glands - 43hair- mostly dead keratinocytes bonded together, forming a column
- har root nourished by blood vessels of pipilla
- as hair lengthens older epithelial cells pushed farther from nutrient source causing cells to keratinize and die
- hair replacement occures within same follicle - 44distrobution of hair- most of body surfaces
- some hairless areas: palms, soles, pamar surfaces of didgets... - 45hair textures- most fine and downy
- some much courser - 46types of hair- lanugo - downy, non-pigmented
- vellus hair - fine pale hairs
- terminal hairs - course, pigmented hairs of scalp... - 47terminal hairs- at puberty, increased in androgen secretion in BOTH GENDERS cause axillary and pubic vellus hairs replacement with treminal hairs
- ar puberty in MALES, vellus hairs on face, chest, limbs replaced with terminal hairs - 48effect of cross sectinal shape of hair shaft- round ~> straight hair
- oval ~> wavy hair
- kidney-shaped ~> curly hair - 49hair structure and development- during embryonic development, stratum basale epidermal stem cells invaginate downward
- hair follicle
- hair martix
- bulb of har
- hair matrix epithelial stem cells contilually dividing to ~> mother stem cell ~> 2 daughters - 50hair follicle- composed of 2 parts:
~> external root sheath
~> internal root sheath (arises fron hair matix
- outside is dermal root sheath - 51hair matrix (bulb matrix)- originally derived from stratum basale
- melanocytes ~> pigmentation of hair root and shaft - 52bulb of the hair- composed of 2 parts
~> hair follicle base
~> dermal root sheath - 53parts of the hair- hair root: part you cant see - in skin
- hair shaft: extends beyond surface of skin - 54concentric layers of hair- medulla: outermost
- cortex: middle with tightly packed pigment granules
- cuticle: outermost layer - 55hair growth cycle- growth stage: cells of hair matrix constantly dividing
- regression stage: stop dividing
- resting stage - 56lifespan of a scalp hair- usually 2-6 years of active growth, followed by replacement
- 57determinants of hair color- amount and type of melanin
- tyrosinase activity level
- replacement of pigment granules with air pickets - 58variations in hair color- effects of emuelanin and pheomelanin
- 59hair loss- electrolysis: using electricity to remove hairs
- alopecia: toemorary or perminany hair loss, producing baldness - 60accessory structures associated with hair loss- hair root plexus
- sebaceous glands
- arrector pili muscles - 61hair root plexus- nerve endings of sensory neuron wrapped around hair follicle
- function: tactile (touch) receptors
~> when hair shaft is touched, hair root plexus ~> action potentials in sensory neuron's axon - 62sebaceous glands- associated with most hairs
- secretory ducts empty into follicle lumen
- function: lubricates hair and anti-microbal - 63arrector pili muscles- smooth muscles attached to the hair folicle
- cold or fear ~> contraction
- functions: traps warm air close to body and defense - 64nails- plats of compacted dead keratinized epidermal cells
- functions: protection, grasping and manipulation, enhances sensitivity of fingertips - 65nail body-part you can see
- free edge: white part at end - 66nail root- cannot see
- under skin - 67nail plate- nail body and nail root
- 68nail matrix- priximal to nail root
- contains epithelial stem cells
- as the nail grows from nail matrix, daughter cells become progressively more keratinized, compacted and dead - 69nail bed- skin under nail plate
- 70eponychium (cuticle)- narrow band at begining of nail (skin)
- 71hyponychium- thickened area of stratum corneum of the nail bed
- 72vascular nail tissue- vasculawr dermal tissue ~> pink nail color
- in cyanosis, color change to blue - 73lunula- white cresent-moon-shaped area
- epidermis is thicker there than anywhere else - 74rate of nail growth- 1mm per week
- different for each person - 75glands- ducted/exocrine glands
- sebaceous glands
- sudoriferous gands
- eeruminous glands - 76sebaceous glands- simple or branched acinar oil glands
- sebaceous glands are absent in skin of palms, soles of feet, fingers, toes
- usually associated with hair follicles ~ but in some areas, ducts open onto skin surfaces
- secrete sebum - 77function of sebaceous glands- lubricate
- soften and waterproof hair and skin - 78comedones of sebaceous glands- if ducts become blocked, secretions accumulate ~> comedones
- whiteheads - skin pores closed
- blackheads - skin pores open
- easily infected and inflamed
- pus-forming bacteria may ~> pimple or boil - 79sudoriferous glands- simple tubular exocrine gland ~ produce sweat ~ transported to skin via gland
- very dense distrobution on palms, soles, forehead - 80types of sudoriferous glands- eccrine sudoriferous glands
- apocring sudoriferous glands - 81eccrine sudoriferous glands- secretroy coil located in deep dermis
- excretory duces open onto most skin surfaces ~ none in lip margins, nail beds, glands penis, clitoris
- during sweat transport through excretory duct, salts reabsorbed - 82function of eccrine sudoriferous glands- thermoregulation
- glands become active when core temprature too high
- evaporative cooling of body - 83apocrine sudoriferous glands- secrete via merocrine mechanism (exocytosis)
- secretory parts located on lower deris or hypodermis
- excretory ducts open into luen of hair follicles
- apocrine sweat much more viscous
- odorless unless contaminated by bacteria
- begining functioning at puberty - 84location of apocrine sudoriferour glands- hair folicles in armpit, anal, pubic, nipple, face of males
- 85functon of apocrine sudoriferour glands- uncertain
- no role in themal regulation
- become active when person is under stress or sexually excited
- no pheramones found - 86eeruminous glands- modified sweat glands in external ear
- secretory ducts open into ear canal
- waxy produce + sebum ~> cerumen (ear wax) - 87function of eeruminous gland- sticky acidic barrier
- anti-microbal - 88functions of the skin- protection
- cutaneous sensations
- synthesis of vitamin D
- thermoregulation
- excretion and absorbtion
- blood reservoir - 89skin protection- protection from physical traumas
- protecton from bacterial invasions
- protection from fluid loss or gain
- UV protection by melanin
- immunity - 90skin immunity protection- intraepidermal macrophaged and T-lymphocytes in epidermis
- macrophages in dermis - 91cutaneous sensations of skin- sensory receptors = nerve endings of sensory neurons, whether free or encapsulated
- 92types of cutaneous skin receptors- touch receptors: merkel cells and disks/ meissner's touch sorpuscles
- pressure receptors: lamellated corpuscles
- pain receptors
- warm and cold receptors
- vibration receptors
- tickle/itch receptors
- hair root plexuses - 93skin synthesis of vitamin D- skin producees vitamin D, from 7-dehyrocholesterol
- hydroxylated by liver and then by kidneys ~> active hormone calcitriol - 94role of calcitriol of synthesis of vitamin D on skin- helps regulate calcium and phosphorus metabolism
- immunoregulation: most immune cells have calcitriol receptors - calcitriol regulates immune function - 95skin thermoregulation- endogenosu heat sourses
- exogenous factors
- mornal body temprature ( 36.2-37.7)
- temprature homeostasis by hypothalamus - 96skin mechanisms for thermoregulation- vasoconstriction and vasodilation
- regulation of activity lvel of eccrine sudoriferous glands ~ sweat ~> evaporative cooling - 97vasoconstriction and vasodilation (thermoregulation)- of dermal blood vessels
- vasocondtriction decreases blood flow to skin
- vasodilation increases blood flow to skin - 98excretion- various small blood solutes are excreted in sweat
- 99absorbtion- hydrophilic substances
- hydrophobic substances
( steroid hormones/ fat soluble vitamins/ organic toxins/ heavy metaals/ gases/ organic solvents) - 100blood resevoir- at rest, dermis revieves 8 - 10% of total caridac output
- during hemmorage, skin's blood reservoir mobilzed - 101wound healing- epidermal wound healing
- deep wound healing - 102epidermal wound healing- resurfacing of basement membrane via,
~> mitosis of stratum basale stem cells epidermal growth factor (EGF)
~> basal epithelial cells detach, migrate across wound surface then stop (due to contact inhabition) reattach and divide then ~> normal skin strata - 103deep wound healing- inflammatory phase
- migratory phase
- proliferative phase
- maturation phase - 104inflammatory phase of deep wound healng- blood clot unites would edges
- inflammatory mechanisms bring in: neorophils and macrophages, mesenchymal cells, nutrients - 105migratory phase- clot ~> scab
- epithelil stem cells migrate under scab, bridging wound
- fibroblasts ~> collagen fibers
- injured blood vessels regrow
- 'granulation tissue' - 106proliferative phase- epithelial cell growth
- haphazard collagen deposition
- ongoing blood vessel growth - 107maturation phase- scab falls off
- orderly collagen deposition - 108collagen deposition (fibrosis)- scar tissue composed of many collagen fibers
- scar matures by cross-linking of collagen
- of extensive fibrosis, accessory structures' functions affected
- few sensory nerve endings, blood vessels, glands or hair
- lighter pigmented and less elastic
- if scaring is excessive, healed wound area elivated
- 2 types - 1092 types of scaring- hypertrophic scar - scar elivated, contained within original broders of wound
- keloid scar (cheloid scar) - not contained within borders of wound
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- Biology Flashcards on biology chapter 5, created by Jaimee Mc on 01/02/2018.
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